1. Field of the Invention
The present invention pertains generally to the field of home entertainment systems, and more specifically to communication and control technologies in home entertainment systems.
2. Background
In the past, a home entertainment system frequently consisted of simply a television set (TV) and a video cassette recorder (VCR). One or two coaxial or composite cables interconnected the TV and VCR from input-to-output and/or output-to-input respectively. However, in recent years, home entertainment systems have become increasingly complex.
Advances in home electronic devices, such as the compact disk (CD) player, digital-video disc (DVD) player, gaming systems, surround sound audio systems, hand held video cameras, etc., naturally compelled consumers to connect the additional devices to their home entertainment system. Each new device added at least two more wires (generally, power and input/output) to the complex web of wires snaking their way in and out of the various devices.
Originally, switch boxes were employed to cut down on the complexity of the interconnections between the various devices. For example, a simple xe2x80x9cA/Bxe2x80x9d switch box allowed a user to selectively choose one input or another, without having to disconnect and re-engage coaxial cables between the devices. As the number of devices in home entertainment systems increased, however, the use of A/B switch boxes to interconnect the devices becomes cumbersome and inefficient.
Notably, consumers generally desire less wires, simpler interconnect schemes and, as the functionality and sophistication of home entertainment devices increase, to dispose of the myriad individual component remote controls needed to operate the respective devices. Indeed, most remote control xe2x80x9cfeaturesxe2x80x9d are never used (see, e.g., xe2x80x9cThe Complexity Problem: Industrial Designxe2x80x9d, Atlantic Monthly, Vol. 271, No. 3, March 1993, p. 96); if for no other reason, this is due to the differing sequences and/or number of steps involved with the control and operation of each respective device.
One solution to the aforementioned control problem is proposed in U.S. Pat. No. 5,675,390 (the xe2x80x9c""390 patentxe2x80x9d) by Schindler et al. As depicted in FIG. 1 of the ""390 patent, an entertainment system is centrally controlled by a personal computer. According to the Schindler et al. system, control is consolidated in the personal computer, wherein a xe2x80x9chub and spokexe2x80x9d, or xe2x80x9cstarxe2x80x9d type communication topology is employedxe2x80x94i.e., with all communications passing through the personal computer (or hub). By this configuration, each device requires its own dedicated connection to the personal computer. Such a solution may work well for tightly integrated home electronics equipment and a sophisticated computer user. However, it requires an even greater number of interconnecting wires than were previously employed. (Note the number of I/O plugs depicted in FIG. 7 of the ""390 patent). Further, such a system is not scalable. That is, as new devices are to be added to the system, additional corresponding adapters/controllers must be added to the personal computer.
A similar solution is proposed in U.S. Pat. No. 5,722,041 (the xe2x80x9c""041 patentxe2x80x9d) by Freadman. FIG. 2 of the ""041 patent best depicts Freadman""s home entertainment system. Like Schindler et al., control is centrally located in a personal computer. Media feeds are through a combination multi-channel modem and analog radio frequency mixer, which connects to a number of terminal devices through a coaxial cable. Although a reduction in the number of wires is accomplished; shared functionality between the devices is minimal, e.g., one device doesn""t control another device and vice-versa.
In particular, adding a user-operated personal computer to control a home entertainment system network does not, in itself, reduce complexity. In fact, it may increase the complexity. The computer is often difficult, if not cumbersome to control. Hardware and software components generally need to be configured to communicate, and the devices properly initialized. Upgrades to either peripheral devices (e.g., VCRs, TVs, etc.) or the computer itself may necessitate a complete overhaul of the system operating software, thereby introducing incompatibilities and uncertainties in the system performance.
With regard to the myriad interconnection wires in more complex home entertainment systems, one solution is the IEEE 1394-1995 standard and its extensions IEEE 1394a, and IEEE 1394b, which are referred to herein as xe2x80x9cIEEE 1394xe2x80x9d. In one embodiment, a IEEE 1394 cable is a six strand cable: one strand for power, one strand for ground, two strands for data, and two strands for strobes used to synchronize the data strands. In an alternative embodiment, a four strand cable can be used, omitting the power and ground strands. IEEE 1394 cable also comprises a shield, which prevents electromagnetic interference. At its core, IEEE 1394 cable is essentially a high performance serial bus, having data rates as of this present writing of up to 400 megabits per second.
Advantageously, the IEEE 1394 bus reduces the need for the myriad wires in a home entertainment system, as the component electronic devices may be designed to receive power and communication through the IEEE 1394 cable, thereby reducing the connections needed for most devices to as few as a single cable in a backplane bus environment. The IEEE 1394-1995 standard provides a specification for aspects of the physical, link and transaction layers for implementing of the IEEE 1394 bus, including provisions for such functions as resetting the bus, bus arbitration, node configuration, standard packet structures, initializing packet transmission, sending and receiving asynchronous packets, sending and receiving isochronous packets, transaction control, and error detection and correction.
Communication over IEEE 1394 bus differs from many previous technologies in that it is purely digital. In particular, data carried on the IEEE 1394 bus is either digital from the source (e.g., a CD-ROM), or it must be converted by an analog-to-digital converter before being placed on the IEEE 1394 bus. Further, communication in a IEEE 1394-based system is peer-to-peer, i.e., each device (a.k.a xe2x80x9cnodexe2x80x9d) on the IEEE 1394 bus can communicate with any other node without requiring communication/control requests to be processed through a central device/node (e.g., as is required in a xe2x80x9cclient-serverxe2x80x9d type configuration). In a IEEE 1394-based system, the controller can reside in any node, so in a sense, the IEEE 1394 bus itself becomes the controller.
Challenges for proponents of IEEE 1394 have been not been so much at the lower layers of operation, that is in the physical, link and transaction layers (although bridges between protocols and data packet structure continue to be areas of contention), but rather in the high layers of the network protocol stack, such as the application layer. Recent developments in the broadcast television and cable industries, such as high definition television (HDTV) and consolidation in the cable broadcast industry are exponentially expanding the number of services and content available to consumers. To this end, interoperability between home electronic devices is strongly desired, as are common and/or standard functionality, ease of use and scalability. As such, there is a need for a system to control and manage the expanding array of devices and services that can be connected and supported, respectively, in a IEEE 1394-based home entertainment system.
In accordance with a first aspect of the present invention, a method is provided for transmitting command and control information between at least two nodes of a network, such as, e.g., an IEEE 1394 based home entertainment network, which includes
dynamically generating a node navigation tree, transmitting the node navigation tree to a video display unit,
receiving a node navigation input identifying a particular node in the node navigation tree,
modifying a subset of the node navigation tree based on the node navigation input,
transmitting the modified subset of the node navigation tree to the video display unit,
generating a node function list including one or more functions pertaining to the identified node,
transmitting the node function list to the video display unit, receiving a node function input corresponding to a particular node function in the node function list, and
transmitting a command to the identified node based on the node function input.
As will be apparent to those skilled in the art, other and further aspects and advantages of the present invention will appear hereinafter.